This invention relates to an apparatus for cost-effectively unwrapping and disposing of stretch film, specifically for unwrapping a palletized shrink-wrapped load.
The most common method for removing stretch film from a pallet having a plurality of items stacked and stretch wrapped thereupon is to manually cut and remove the stretch film from the items. The manual cutting and removal of the stretch film is relatively time consuming, dangerous, and costly.
Apparatuses have been proposed to automatically remove stretch film or other wrapping from a load. U.S. Pat. No. 5,148,651 to Masuda (1992) discloses an apparatus designed to unwrap a palletized stretch-wrapped load while preventing the articles from falling off of the pallet. The Masuda apparatus includes first and second upright frames. The first upright frame includes two lower grippers and an elevated cutting unit. The second upright frame includes a carriage having a platen to press the top of the load and a pair of swing arms symmetrically arranged on either side of the platen and extending toward the first upright frame. Upper grippers are secured to the swing arms. In operation, the palletized and stretch-wrapped load is positioned between the first and the second upright frames. The platen is moved downwardly to press the top of the stretch-wrapped load. The lower grippers are operated to grip the stretchable film and separate a lower portion of the stretchable film from the load. The upper grippers grip the upper edge of the stretchable film and the cutting unit moved to a position near the top of the load, cuts the stretchable film. The lower grippers release the lower edge of the stretchable film and the upper grippers move upward. When the stretchable film is fully separated from the palletized load, a pusher is moved toward the rearward shifted stretchable film to push it into a collecting guide and discharge nip rollers may be driven. It is noted that the driving of many of the components is done through pneumatic cylinders.
U.S. Pat. No. 5,725,349 to Garvey (1998) discloses an apparatus designed to remove shrinkwrap from a plurality of bottles encased in the shrink-wrap and arranged in the form of a substantially rectangular package. The Garvey apparatus includes a base frame having an upper support surface with a first and a second cutting assembly extending upwardly through the upper support surface. A pusher is connected to the base frame and is adapted to move the package along the support surface over the first cutting assembly in order to effectuate a lengthwise cut in the bottom of the package. Likewise, a second pusher is secured to the base frame and is adapted to move the package across the support surface over the second cutting assembly to effectuate a widthwise cut in the bottom of the package. The Garvey shrink-wrap removing apparatus also includes a debagging station for removing the shrinkwrap from the plurality of bottles.
U.S. Pat. No. 5,911,666 to Lancaster (1999) discloses an apparatus for removing xe2x80x9cplastic packaging materialxe2x80x9d from a wrapped load. A stream of air is applied to a region of the packaging material on the load at a sufficient temperature, volume, and velocity to cause the packaging material to be weakened for separation in the selected region. Generally, it is preferable to heat the stretch wrap packaging material to a temperature of at least about 170xc2x0 F. Lancaster also discloses a turntable for removing the packaging material from the load. A mandrel assembly may be included to receive and collect the packaging material. The mandrel assembly may be used to wind up the packaging material to form a rolled bale, the bale being of about the height of the load or the height of the wrapped packaging material on the load. The Lancaster apparatus has several drawbacks. The hot air can damage or deform the plastic bottles contained on the palletized loads. The apparatus requires extensive energy consumption. Additionally, the Lancaster apparatus requires several additional parts, such as blowers, and poses a danger to workers. The turntable method of spinning the load to remove the stretch film makes it difficult to add the Lancaster to an existing conveyor system and would require several additional parts and would be expensive to retrofit. The Lancaster apparatus uses a large, complicated, and heavy mandrel mechanism to gather the stretch film and produces heavy, tall, and unstable xe2x80x9crolled balesxe2x80x9d again making it more expensive to make and maintain and these bales are extremely dangerous to workers. Further, the Lancaster apparatus requires considerable floor space that in many cases makes it impractical to use.
The present invention provides a cost effective, low-maintenance, and ergonomic apparatus for removing stretch film from a pallet having a plurality of items, such as bottles, stacked thereupon.
The present invention includes an unwrapping apparatus for removing and disposing of stretch film or other wrapping from a plurality of articles palletized on a pallet. The apparatus includes a frame made up of at least two upright legs. The upright legs are operatively connected to maintain a space therebetween, the space being suitable for accommodating the palletized load. Two lower grippers, one connected to a lower portion of each leg, are included for engaging the film and pulling the film from the wrapped load. The lower grippers are movable toward and away from the load to effectuate the pulling of the film. Further included are two upper grippers, one connected to an upper portion of each leg, also configured for engaging the film and pulling the film from the wrapped load. The upper grippers are movable toward and away from the load. A cutting unit including a cutting tool for cutting the film is connected to one of the upright legs and is movable upward and downward, toward and away from the load. Further provided are a spooler unit, consisting of an integrated spooler and stripper units, and a pinch roller. The spooler unit is connected to one of the upright legs. The spooler unit maintains the proper tension of the film during the collection of the film and collects the film after it has been removed. The stripper unit removes the collected film from the spooler.
In operation, the unwrapping apparatus of present invention receives the load with the swing arms in an open or load pass position. When the load is positioned, for example via conveyor, for unwrapping, the two lower gripper arms are moved towards the load such that the gripper jaws protrude into the stretch wrap in such a manner as not to disturb the container lattice. The grippers preferably include jaws for effectuating such a protrusion. The lower grippers are actuated to grip the wrap. The lower grippers arms are then retracted to move the grippers away from the load, thereby pulling the wrap away from the load. The cutting unit is positioned at the bottom of the load and moved upwardly. The cutting tool engages the wrap for cutting as the cutting unit moves upwardly; the cutter unit is moved upwardly until it reaches the upper gripper height. Once the cutting unit has reached the upper gripper height, the upper gripper arms are actuated to move toward the load. The upper grippers engage and grip the wrap and the cutting unit completes the upward cutting of the wrap. With the wrap cut from bottom to top and the grippers gripping the wrap, the arms are actuated away from the load. The load is conveyed away with the wrap suspended by the grippers. All but one gripper release the wrap, the final gripper being actuated to continue its arc and threads the wrap through the pinch roller and spooler spindles. Once threaded, the spooler rotates to captivate the wrap, the final gripper is released and moved away, and the spooler continues to rotate, pulling the wrap through the pinch roller squeezing the air out of the wrap and is continually rotated until the entire wrap is spooled. The stripper is actuated to remove the spooled wrap from the spooler spindles. One of the upper grippers is used to knock the spooled wrap off of the stripper and into a bin.
The design of the apparatus makes it relatively inexpensive to produce and reduces the manufacturing cost of removing stretch film from a palletized load of bulk containers, such as bottles.